This application claims the priority benefit of European Patent Application No. EP 01 120 439.3 and German Utility Model Application Nos. DE 201 14 120.5 and DE 201 14 103.5, all filed on Aug. 27, 2001.
Not Applicable
The invention relates to electrical connectors, in particular, highly stressed electrical plug-type connectors for motor vehicles and the like, which serve for transmitting control signals and/or for power supply.
Standards in which important dimensions and codes for interchangeability are defined apply to plug-type connectors of this type. For example, a German standard for highly stressed two-pole to four-pole electrical connectors for road vehicles which contain round contacts and a bayonet coupling is DIN Standard 72585-1 and -2 of March, 1996. Seven-pole embodiments are also used. These connectors are intended for providing an electrical connection with components that are directly mounted on an internal combustion engine. Consequently, the connectors must be able to withstand high thermal and dynamic stresses. However, high stresses also occur when the connector is used on other fixed installations and with free-floating connectors within the line system or main system.
Primary and secondary locking elements are provided for the connector terminals in order to improve the reliability of the connector. Such secondary locking elements or retainers frequently have a complicated design and are difficult to insert.
An object of the present invention is to provide an electrical connector, in particular, according to DIN Standard 72585, which can be easily handled. The object of the present invention is solved by the subject matter of claim 1. Advantageous further developments are defined in the dependent claims.
The electrical connector according to the invention cannot only be handled much easier, but also provides significant technical advantages as described in greater detail below. The disclosed design of the electrical connector provides efficient use of material for manufacturing the components and thus allows an economic use of the materials.
In contrast to conventional designs in which the secondary locking element is inserted from the terminal receiving end of the housing corresponding to the side of the housing where the connecting leads protrude, the invention of claim 1 provides a connector housing in such a manner that the secondary locking element can be inserted from the opposite mating end of the housing. This simplifies and accelerates the assembly because it is no longer required to thread the connecting leads through the secondary locking element. Until now, the secondary locking element was commonly inserted from the terminal receiving end and locked in position after the housing was equipped with the terminals provided with the leads. An insertion chamber for receiving the secondary locking element, in combination with openings in the terminal receiving cavity walls, allows insertion of the secondary locking element with one hand from the mating end of the housing that is free of leads and to lock the terminals therein by means of xe2x80x9csecondary interlocking,xe2x80x9d namely with the aid of locking knobs or lugs that protrude through said openings.
It is preferred that the secondary locking element can be inserted in an angular position relative to the housing in which the secondary locking element is located in a non-locking position. In this non-locking position, the terminal receiving cavities can be equipped with the terminals from the terminal receiving end of the housing without being obstructed by the locking knobs. The terminals are then retained in the terminal receiving cavities by means of xe2x80x9cprimary lockingxe2x80x9d. This provides the advantage that the secondary locking element can be inserted before the housing is equipped with the terminals and can subsequently be rotated into its locking position.
It is preferred that parts which prevent effecting a connection with an electrical connector counterpart are integrally formed on the secondary locking element. In the non-locking position, radially extending xe2x80x9ccover bladesxe2x80x9d cover the mating side end of at least one terminal receiving cavity, preferably three terminal receiving cavities, such that the terminal receiving cavities can only be accessed from the mating end in said locking state. In an exclusively four-pole embodiment, it is possible to provide only a single cover blade. However, the number of cover blades needs to be chosen such that no more than one empty, not occupied cavity is exposed in the non-locking position. This additional further development relates, in particular, to a secondary locking element for a socket housing which is described further below.
Alternatively, coding and/or guide means which commonly are integrally formed on the housing are provided on the secondary locking element of the present invention and said means being angularly offset relative to their normal intended position in the non-locking position of the secondary locking element. The angular offset is only removed when the secondary locking element is in the locking position and in this locking position a connection with the connector counterpart can be effected. This additional feature relates, in particular, to a secondary locking element for a pin housing that is described further below. In the non-locking position, the secondary locking element is secured from falling out of the housing by a catch tab.
The handling and the assembly of a connector system are additionally simplified due to a special design of a coupling ring that can be snapped into an angular position which exactly defines the mating position or so-called zero position in which the electrical connector can be electrically connected to an electrical connector counter part.
A through-opening in the coupling ring which accommodates a firmly fitted safety pin with a predetermined breaking point can be used as an alternative to the commonly used system with complicated and hardly manipulation-proof lead sealings with a lead wire and lead eyelets. This advantageous further development of the present invention also represents an independent solution for increasing the safety against manipulations on connectors with a coupling ring in general, which can be easily handled (without tools or assembly aids). If tensile or torsional forces are exerted upon the safety pin according to the invention, fracturing or shearing occurs at the predetermined breaking point such that a manipulation can be easily detected.
According to another and also independent aspect of the invention, the handling of electrical connectors to be mounted is significantly improved due to an elastically deformable self-locking snap-on nut. The self-locking nut according to the invention does not have to be screwed over all thread turns of an outer thread until it is in the tightened position, but can be snapped onto the outer thread into a lowest position in a click-stop manner and can subsequently be tightened.
Threadless chambers of the outside thread and resiliently and integrally formed-on or molded-on thread segments of the self-locking nut are provided for achieving a self-locking effect. The handling also becomes easier and more reliable by providing an inclined starting surface at the leading end and a stopping edge at the trailing end of the thread segments of the nut as defined in corresponding dependent claims.
In contrast to conventional nuts, the inside diameter of the self-locking nut according to the invention is, in the preferred embodiment, smaller than the nominal size or dimension of the thread. This is achieved by offsetting the thread segments radially inwardly relative to the nominal thread size. When the nut is screwed on, the self-locking effect is achieved due to the fact that a thread segment engages or immerses into one of the aforementioned threadless chambers. The curvature radius of the thread segments of the self-locking nut preferably is identical to the curvature radius of the mating thread, in this case, the threaded section of the connector housing.
The self-locking effect may, according to an alternative embodiment, also be achieved by providing the self-locking nut with a slightly smaller thread size than that of the mating thread. However, this has the disadvantage, in particular, with smaller thread sizes, that the handling becomes more complicated. In certain instances, it may even become impossible to screw on the nut.
The design of an end cap that can be mounted on a cylindrical end section of the housing and comprises a specially designed tension relieving device for an electric cable represents another independent aspect of the invention. Particularly, the invention is also directed to a tension relieving device for an electric cable independent of its application. Hence, the cap or parts of the cap are only an example of any suitable mounting or installation base or component.
According to the invention, the tension relieving device comprises two symmetrical, elastically flexible clamping members in the form of webs, ribs or fins that extend transversely and are obliquely inclined opposite to the direction of the tensile force, i.e. with respect to the longitudinal direction or axis of the cable to be relieved. The clamping members or webs are preferably slotted like a comb. More particularly, each clamping member has a free end and a mounting or attachment portion that is integrally formed on a mounting base. Beginning from the end the clamping members are slotted in direction towards the mounting end. Preferably, the slots extend parallel to one another so that the comb teeth formed due to the slots also extend parallel to one another and are preferably in one plane. Due to this feature, the cables are secured against tensile forces more reliably than it is the case with conventional transverse ribs that extend vertically.
Cables of different diameters can be reliably held according to an additional further development in which one clamping web of the previously described type respectively is integrally formed in each of the two end cap parts. In this case, the clamping webs symmetrically oppose one another in the assembled end cap and preferably define a flat, lenticular free cross section. In this manner, the comb teeth of the slotted webs circumferentially surround the cable. The short axis of this cross section corresponds to the minimum diameter of cables that can be held in position, with the long axis corresponding to the maximum diameter.
According to the invention, an annular self-locking head section of an end cap part of the connector also ensures a simplified handling. The end cap part provided with the annular head section can be mounted on the housing before the housing is equipped with the contacts. This preassembly was impossible in conventional solutions with hinged end cap parts, namely because these end cap parts can only be attached after the housing has been equipped with terminals and cables. This aspect of the invention advantageously can be generally applied to connectors with an end cap, i.e. it is also an independent aspect of the present invention.
The head section preferably contains elastically deformable catch blades that have the shape of ring segments. According to a further development, the mounted head section is secured by means of a safety pin.